Thomas Vaughan: Mold making: Hands

I can tell you now, this is going to be a very .... very long post.

So sit back, relax and I'll show the process for molding up Max's hands!

The material I will be claying up with is a water based clay (Don't know the brand, I got it from uni) The good thing about using a water based clay to clay up with. is that it's very easily malleable and removing chunks of clay is easy. Another good reason is that when it comes to smoothing the clay and removing the clay from the plaster further down the line, water will dissolve remove the clay very easily!

I should also note that it's always best to clay up in a different material to what you sculpted in! as like I said when it comes to removing the clay later the water will break down the clay but my sculpt will be un harmed as they are an oil/wax based clay!

I cut and rolled a piece of clay out and smoothed it down to get it flat. I then placed my sculpts on top to see where they should be positioned and whether I had enough room for them.

Once I was happy with the positioning and give myself plenty of room around the sculpts I then drew a basic outline around the sculpts.

The hands were then removed and I began removing the clay where the hand should be. The hole for the hand should half the depth of the hand as seen in the images below.

The process was then repeated on the other hand.

Once both hand where halfway submerged below the clay I then started pushing and adding more clay around the sculpt to ensure there was no gap where the joining of the clay and sculpts met and to ensure they were flush to one another.

This is to ensure that when the plaster is poured, no plaster makes its way to the other half of the sculpt!

As well as this 'keys' were made out of plasticine (these don't have to be a different clay, I just wanted the picture to look nice!). Keys are used to ensure when both halves of the mold are done they can register to one another without shifting.

Everything was now ready, for me to box up.

To do this I prefer to use foam board as it very sturdy, therefore I know when I pore the plaster in it's not just going to fall apart on me. And also the foam can be cut halfway through the paper and the foam to allow you to bend the board without having to glue the pieces back!

THe foam board was placed and cut to fit around the clay and the next step was for me to hot clue everything together!

On to pouring the mold!

I had to clay up and mold all of my sculpts within a week therefore I was creating the mold late in to the night and unable to go to uni to pour them. Therefore my bathroom had to do! Good thing about this is, if I spill any plaster, it can come away from the titles very easily!

So in the photo below you'll see what my molding equitment are.

I have my clayed up sculpts boxed in. I usually put a mat or cling film underneath, just incase i spill any plaster while pouring. I have a bowl of water (big enough to pour the plaster in and mix thoroughly without spilling the contents everywhere). A bucket of plaster. And some clay on the side, this hasn't got to be any specific clay, it's just incase plaster seeps through a gap of the foam board that I might have missed with hot glue.

When mixing my plaster I do not throw the bucket of plaster in to the water. I take handfulls and slowly add it to the water. When small islands appear on top of the water, thats when I know I have enough plaster ratio to water and I start mixing.

The plaster tends to get quite warm and begins curing relatively quickly, therefore ytou don't have a lot of time between starting mixing and pouring the contents in to the box therefore I don't have a photo of that.

But here's the first half of the mould finished!

(There were no holes in the foam board, so I didn't need to use the spare clay)

Once the plaster is set, the clay can be removed, careful not to remove the sculpts from the mould in the process! The other side of plaster still needs to be poured.

Learning from Mistakes

(Tip)

Although during my first year, the hands did come away from the plaster but as long as you can put them back in and ensure there is no gap for the seconds half of plaster to creep under you should be fine!

What happened in first year is that I left the first half of the mould and the clay together overnight and when I came to remove the clay, I believe the clay had hardened and basically griped on to the sculpts and pulled them away from the mould. But all was Fine, I would just advise to remove the clay from the sculpts as soon as the plaster has cured!

All was good with this mold though!!

I took the big chunks of clay off then with the smaller bits closer to the sculpt, I used a brush and water and started brushing the clay away!

This is how they looked after they were cleaned

Plasticine was then added to the mold to cover 'dead space'. This is to prevent the plaster from the 2nd half of the mold getting stuck here, therefore this will then limit the amount of surface area which are touching on the 2 molds and will then make it easier for them to be pulled apart from one another. The plasticine being towards the edge of the mold will also act as a screwdriver hole, for the screwdriver (doesn't have to be a screwdriver,just my preference) to prise open the 2 halves.

A release agent MUST be used at this stage on the first half of the plaster to ensure when the second half of plaster is poured, it doesn't adhere to the first half and trap your sculpts!

My routine is usually to spray a release agent spray on the plaster and then brushing a thin layer of vaseline on to the plaster as well.

(Putting just one or the other on to the plaster to act as a release agent would work great, it's just Im paranoid so I have to put the two on just in case)